This invention relates generally to axial-thrust bearings and more particularly to a thrust bearing roller assembly that provides lubricant flow through the bearings to other components of a rotating machine.
There are two basic categories of bearing retainers, two piece assembled retainers and single piece wraparound retainers. A wraparound retainer is a single annular ring having a plurality of roller pockets for holding the bearing rollers. Typically, the sides of the pockets extend outward into fingers that wrap around and retain the roller. With many one-piece designs, it is difficult to ensure sufficient roller contacting surface or wrap-around and the single piece retainer usually requires special heat-treating.
A two piece retainer usually consists of two retainer halves, each half containing a plurality of roller pockets. The retainer halves are aligned with the pockets in alignment and then the two retainer halves are mechanically joined. These two-piece retainers have fair wrap-around and conformity to the roller shape.
A drawback of both single and two piece retainers is the necessity for lubricant to overcome considerable flow resistance in order to flow through the bearing. The resistance is caused in part by the narrow spaces between the rolling elements and the pockets on the retainers. The resistance is magnified in two piece retainers as there are two sets of pockets that the lubricant must flow through in order to pass through the bearing.
The foregoing illustrates limitations known to exist in present roller thrust bearings for use in rotating machines. Thus, it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.
The present invention relates to a roller retainer assembly for an axial-thrust bearing. The assembly comprises first and second annular retainer plates. At least one first roller pocket extends through the first annular plate and is defined by opposed first side edges and a first radially inner edge opposed with a first radially outer edge. At least one second roller pocket extends through the second annular plate and is defined by opposed second side edges and a second radially inner edge opposed with a second radially outer edge. The first and second annular retainer plates are interconnected such that the at least one first roller pocket is substantially circumferentially aligned with the at least one second roller pocket. The first roller pocket inner edge is radially offset a distance Y from the corresponding second roller pocket inner edge and the first roller pocket outer edge is radially offset a distance X from the corresponding second roller pocket outer edge, thereby defining at least one roller retaining area for receipt and retention of at least one roller. The roller retaining area is defined by the first and second opposed side edges and the first radially inner edge and the second radially outer edge. As such, the first pocket defines a first fluid passage gap through the first annular plate between the roller and the first outer edge and the second pocket defines a second fluid passage gap through the second annular plate between the roller and the second inner edge.